tracing for RenderTextMac::GetDisplayText() eliding goo

crashes:

 thread #1: tid = 0x963d40, 0x00007fff88adea99 CoreFoundation`CFDictionaryGetValue + 25, queue = 'com.apple.main-thread', stop reason = EXC_BAD_ACCESS (code=EXC_I386_GPFLT)
    frame #0: 0x00007fff88adea99 CoreFoundation`CFDictionaryGetValue + 25
CoreFoundation`CFDictionaryGetValue + 25:
-> 0x7fff88adea99:  movq   (%r15), %rax
   0x7fff88adea9c:  testq  %rax, %rax
   0x7fff88adea9f:  je     0x7fff88adeae0            ; CFDictionaryGetValue + 96
   0x7fff88adeaa1:  leaq   -0x1046f690(%rip), %rcx   ; __CFConstantStringClassReferencePtr
(lldb) bt
* thread #1: tid = 0x963d40, 0x00007fff88adea99 CoreFoundation`CFDictionaryGetValue + 25, queue = 'com.apple.main-thread', stop reason = EXC_BAD_ACCESS (code=EXC_I386_GPFLT)
  * frame #0: 0x00007fff88adea99 CoreFoundation`CFDictionaryGetValue + 25
    frame #1: 0x00007fff88b4b7a9 CoreFoundation`CFAttributedStringSetAttribute + 297
    frame #2: 0x000000010214062d libgfx.dylib`gfx::RenderTextMac::ApplyStyles(this=0x00007fff5fbfe7a0, attr_string=0x0000000105706840, font=0x000000010510ee20) + 557 at render_text_mac.cc:248
    frame #3: 0x0000000102140228 libgfx.dylib`gfx::RenderTextMac::EnsureLayout(this=0x00007fff5fbfe7a0) + 408 at render_text_mac.cc:168
    frame #4: 0x0000000100197781 gfx_unittests`gfx::RenderTextTest_Mac_ElidedText_Test::TestBody(this=0x0000000105102f60) + 1073 at render_text_unittest.cc:2634
BUG=

[tapted, 2015-03-02 23:41:51]

Output without the SetDisplayRect(gfx::Rect(0, 0, 200, 10));

[ RUN      ] RenderTextTest.Mac_ElidedText
[51049:1287:0303/104008:1113559686074189:INFO:render_text_mac.cc(118)]
OnLayoutTextAttributeChanged: This is an example.
[51049:1287:0303/104008:1113559687465267:INFO:render_text_mac.cc(118)]
OnLayoutTextAttributeChanged: This is an example.
[51049:1287:0303/104008:1113559687515970:INFO:render_text.cc(1285)] Elide: 'This
is an example.' 122, 0, 4
[51049:1287:0303/104008:1113559687613491:INFO:render_text_unittest.cc(2630)]
0x16
[51049:1287:0303/104008:1113559687672296:INFO:render_text.cc(534)] in
SetDisplayRect.
[51049:1287:0303/104008:1113559687690738:INFO:render_text.cc(542)] via set
display rect:
[51049:1287:0303/104008:1113559687704870:INFO:render_text_mac.cc(118)]
OnLayoutTextAttributeChanged:
[51049:1287:0303/104008:1113559687716613:INFO:render_text.cc(1285)] Elide: 'This
is an example.' 1, 0, 4
[51049:1287:0303/104008:1113559687740847:INFO:render_text_unittest.cc(2633)] 0,0
0x16
[       OK ] RenderTextTest.Mac_ElidedText (6 ms)

output with:

[ RUN      ] RenderTextTest.Mac_ElidedText
[51099:1287:0303/104132:1113644088126276:INFO:render_text.cc(534)] in
SetDisplayRect.
[51099:1287:0303/104132:1113644088234150:INFO:render_text_mac.cc(118)]
OnLayoutTextAttributeChanged: This is an example.
[51099:1287:0303/104132:1113644089627819:INFO:render_text_mac.cc(118)]
OnLayoutTextAttributeChanged: This is an example.
[51099:1287:0303/104132:1113644089756051:INFO:render_text_unittest.cc(2630)]
121x16
[51099:1287:0303/104132:1113644089796618:INFO:render_text.cc(534)] in
SetDisplayRect.
[51099:1287:0303/104132:1113644089807809:INFO:render_text.cc(542)] via set
display rect: This is an example.
[51099:1287:0303/104132:1113644089820438:INFO:render_text_mac.cc(118)]
OnLayoutTextAttributeChanged: This is an example.
[51099:1287:0303/104132:1113644089832071:INFO:render_text.cc(1285)] Elide: 'This
is an example.' 122, 60, 4
[51099:1287:0303/104132:1113644090043879:INFO:render_text_mac.cc(118)]
OnLayoutTextAttributeChanged:
[51099:1287:0303/104132:1113644090065480:INFO:render_text_mac.cc(118)]
OnLayoutTextAttributeChanged:
[51099:1287:0303/104132:1113644090075997:INFO:render_text_mac.cc(118)]
OnLayoutTextAttributeChanged:
[51099:1287:0303/104132:1113644090085187:INFO:render_text_mac.cc(118)]
OnLayoutTextAttributeChanged:
[51099:1287:0303/104132:1113644090111410:INFO:render_text_mac.cc(118)]
OnLayoutTextAttributeChanged: …
[51099:1287:0303/104132:1113644090341028:INFO:render_text.cc(1318)]  added
elipsis of width: 14
[51099:1287:0303/104132:1113644090396026:INFO:render_text_mac.cc(118)]
OnLayoutTextAttributeChanged: This is a
[51099:1287:0303/104132:1113644090431174:INFO:render_text_mac.cc(118)]
OnLayoutTextAttributeChanged: This is a…
[51099:1287:0303/104132:1113644090448396:INFO:render_text.cc(1354)] text set to:
This is a…
[51099:1287:0303/104132:1113644090526157:INFO:render_text_mac.cc(118)]
OnLayoutTextAttributeChanged: This
[51099:1287:0303/104132:1113644090559814:INFO:render_text_mac.cc(118)]
OnLayoutTextAttributeChanged: This…
[51099:1287:0303/104132:1113644090575680:INFO:render_text.cc(1354)] text set to:
This…
[51099:1287:0303/104132:1113644090648581:INFO:render_text_mac.cc(118)]
OnLayoutTextAttributeChanged: This i
[51099:1287:0303/104132:1113644090681818:INFO:render_text_mac.cc(118)]
OnLayoutTextAttributeChanged: This i…
[51099:1287:0303/104132:1113644090708670:INFO:render_text.cc(1354)] text set to:
This i…
[51099:1287:0303/104132:1113644090802763:INFO:render_text_mac.cc(118)]
OnLayoutTextAttributeChanged: This is
[51099:1287:0303/104132:1113644090837414:INFO:render_text_mac.cc(118)]
OnLayoutTextAttributeChanged: This is…
[51099:1287:0303/104132:1113644090853671:INFO:render_text.cc(1354)] text set to:
This is…
[51099:1287:0303/104132:1113644090928723:INFO:render_text_mac.cc(118)]
OnLayoutTextAttributeChanged: This is
[51099:1287:0303/104132:1113644090963339:INFO:render_text_mac.cc(118)]
OnLayoutTextAttributeChanged: This is …
[51099:1287:0303/104132:1113644090979647:INFO:render_text.cc(1354)] text set to:
This is …
[51099:1287:0303/104132:1113644091059214:INFO:render_text.cc(1391)] returning
This is …
[51099:1287:0303/104132:1113644091095489:INFO:render_text_unittest.cc(2633)] 0,0
60x16
Received signal 11 SEGV_MAPERR 000000000018